Telephone system.



6 SHEETS-SHEET l.

PATENTED OCT. 18, 1903.

O. B. SMITH.

. TELEPHONE SYSTEM. APPLICATION FILED P183. 3. 1899. RENEWED 001:. 22.1902.

' N0 MODEL.

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PAIENTED OUT. 18, 1903.

APPLIGATION FILED PEE -331899, RENEWED 001122 1902.

6 SHEETS-SHEET 2.

no MODEL,

HE NORR!) PETERS co Pnowqnnu WASHINGTGH u c PATENTED OCT. 13, 1903.

C. B. SMITH. TELEPHONE SYSTEM. APPLICATION FILED FEB. a. 1899. RENEWEDOCT. 22. 1902.

e SHEETS-SHEET a.

NO MODEL.

No. 741,282. PATENTED 001". 13, 1903. 0. B. SMITH. TELEPHONE SYSTEM.

APPLIGATION FILED FEB. 3. 1899. RENEWED OCT. 22. 1902.

N0 MODEL. 6 SHEETS-SHEET 4.

THE Nonms vsvsns c0,PnoroMmrLwAsnmcnox,11c.

PATENTED OCT. 13, 1903.

O. B. SMITH.

TELEPHONE SYSTEM.

APPLICATION FILED FEB. 3. 1899. RENEWED 001?.22.1902.

6 SHEETS-SHEET 5.

N0 MODEL.

No. 741,282. PATENTED OCT. 13, 1903. G. B. SMITH.

TELEPHONE SYSTEM.

APPLICATION FILED FBB.3.1899. RENEWED 0GT,22,1902.

N0 MODEL. 6 SHBET SSHBET 6.

amen/boa Patented October 13, mos.

PATENT rrrcn.

CHARLES E. SMllH, OF NEW YORK, N. Y.

TELEPHONE SYSTEM.

EPEGIFIGATION forming part of Letters Patent No. 741,282, dated October13, 1903.

Application filed February 3,1899. Renewed October 22, 1902. Serial No.128,245- (No model.)

To ctZZ whom it may concern.-

Be it known that I, CHARLES B. SMITH, a citizen of the United States,residing in New York city, county and State of New York, have inventedcertain new and useful Im provements in Telephone Systems, of which thefollowing is a specification.

My invention relates'more particularly to the class of telephone systemswhich embrace a central office with accessories and circuits.

leading therefrom, each having a plurality of stations or telephoneinstruments and their accessories, which circuits are commonly known asparty-lines.

One object of my invention is to enable instruments at a central officeto select and make connection with an idle conductor or a pair of idleconductors from a plurality of conductors on a party-line, so as toenable instruments in a calling-station to select and make electricalcircuit with the same selected idle conductor or conductors, and to alsoenable the correspondinginstruments in a called station to select andmake electrical connection With the same conductor or pair ofconductors. By means of the devices I use one subscriber can callcentral over such selected conductor without producing a signal inanother station, and the telephone instruments in the calling and acalled station may be connected for telephonic purposes over theconductors selected for them at the central office. In carrying out thisportion of my invention I provide a central office and party-linesleading therefrom, each party-line having a plurality of conductorsWhose circuits are normally open, and at central I provide for eachparty-line instruments to select an idle circuit, which instrumentsembrace a movable arm and electrically-operating devices and circuitsarranged to cause said arm to come to rest in connection with one of theidle circuits and to disregard such circuits as may be in use toestablish a calling-line to central for the outlying stations, anddevices are also arranged at central for connecting the telephonethereat with such selected conductor. At the outlying stationsinstruments are provided to select the same conductor that has beenselected at central to enable a call to be sent to central whiledisregarding a conductor that is in use and also to establish a circuitfor the telephones at the stations over such selected circuits. By thismeans the devices at central connected with a party-line normally keepan idle conductor in condition to be selected by a calling subscriber,and after said subscriber has appropriated such conductor and hasobtained a circuit with the party desired the devices at central canselect anotheridle conductor to be used by an other subscriber on theparty-line. At central suitable devices, such as jacks and plugs, areused to connect different party-lines.

Another object of my invention is to enable the operator at central toconveniently connect the telephone thereat with the selected wires ofa'calling and a called station.

A further object of my invention is to provide improved devices both atthe central office and at the outlying stations for enabling central toconveniently select and signal the station desired. In carrying out thisportion of my invention I provide each party-line with main conductorsleading from central through the stations, one of which conductors Iterm an operating-line, another I term a calling-line, and the other arestoringline, and in each station there are connected with theseconductors devices adapted-to be operated by electrical impulses sentover the various lines from central to first select and place in circuitthe signaling instrument of the station desired and after suchinstrument is operated to restore the various devices and circuits totheirnormal conditions. At central is provided an instrument adapted tosend the Various impulses over said conductors to effect the operationsof the instruments at the various stations. At central, also there areprovided switching devices to enable the appropriate impulses to be sentover the various party-lines from the central officeimpulse-transmitting instrument.

The invention also consists in the novel details of improvement thatwill be more fully hereinafter set forth and then pointed out in theclaims.

Reference is to be had tothe accompanying drawings, forming part hereof,Wherein Figure 1 is a diagrammatic View illustrating a central officeand a party-line leading therefrom embracing two stations, showing thetelephones at such stations connected in a closed metallic circuit andthe arm at central in connection with the conductors in use by saidstations. Fig. 2 is a diagrammatic view of the telephone portion of thepartyline system shown in Fig. 1, but showing the arm at central inconnection with a different pair of conductors and the devices at thestations in their normal conditions when not in use. Fig. 3 is a viewsimilar to Fig. 2, but showing the devices at one station as havingselected the pair of conductors that are in connection with the arm atcentral, the devices at the other station being in their normalconditions, but capable of selecting the same pair of conductors. Fig. 4is a diagrammatic view showing two party-lines leading from the centralotiice and illustrating the devices at central for connecting twoparty-lines together and also illustrating the devices at central forenabling a call to be sent over any party-line from the call-producingdevices at central. Fig. 5 is an enlarged detail face view of thedevices adapted to select idle conductors. Fig. 6 is a side View of thesame looking from the right in Fig. 5. Fig. 7 is a detail plan view ofthe arm-controlling magnet and its detent. Fig. 8 is a detail face Viewof the devices at the subscribers stations for selecting the signalinginstrument desired and restoring the circuits to their normalconditions. Fig. 9 is a side view thereof, part being broken away,looking from the right in Fig. 8. Fig. 10 is a detail plan view of themagnet and its armature used in said devices. Fig. 11 is an enlargeddetail view, part being broken away, of the devices at central fortransmitting impulses over the subscribers selecting and callingcircuit; and Fig. 12 is aside view'of the same complete looking from theright in Fig. 11.

Similar numerals and letters of reference indicate corresponding partsin the several views.

Iwill firstdescribe the party-line telephonecircuits, including thearrangements by which idle conductors are selected at central and thearrangements by which a subscriber calls central, and the telephoneinstruments of two subscribers are placed in circuitoverselected idleconductors, and I willthen describe how the operator at central callsthe desired station on any party-line.

A indicates generally a central office at which are located the devicesto be hereinaf ter described, and B, B, B 0, and (3 indicate stations ontelephone-circuits or partylines leading from central, at which stationsare located telephone instruments and devices for connecting suchinstruments with the appropriate conductor of the circuit or party-line,and devices are also located at said stations to enable central toselect and call the desired station. For the sake of clearness ofillustration I have omitted from the drawings the transmitters,inductioncoils, local circuits, &c., that are usually used inconjunction with the receivers shown.

Each party-line has a plurality of conductors for telephonic purposesand for calling central. In the drawings I have shown four conductors orwires 1 2 3 4, forminga party-line leading from central through thestations, and by preference I utilize such conductors in pairs forforming a closed metallic circuit for the telephone instruments. In thearrangement shown the conductors 1 2 constitute one pair and 3 4 theother pair; but it will be understood that said conductors can be usedindividually or separately to form grounded circuits. At central theconductors 1 2 3 4 lead to contacts 1 2 3 4, and other similar contactsare shown for connection with other such conductors if they are used ona party-line. It will be seen that the contacts 1 2 form one pair and 34 another pair, and between these pairs'of contacts is locatedinsulation 5, so that one contact, as 2 4, can act to press the oppositecontact, as 1 or 3, into electrical engagement with a long contact 6without establishingcircnit between the contacts forming pairs. Atcentral are located devices for automatically selecting any conductor orpair of conductors that are not in use or are idle, (and for thereuponholding the corresponding contact 1 or 3 in connection with the contact6,) whereby an .initial or normal circuit is established to central toenable a subscriber to call central, and these devices operate bothmechanically and electrically. The arrangements I have shown for thepurpose are as follows: 7 is an arm secured to or hung upon a shaft8,suitably supported, and 9 is a handle for manually operating the arm 7.The arm 7 is preferably composed of an electric conductor, such asmetal, (or it may carry a conductor,) and by preference carries a roller10,that is adapted to engage the contacts 2 4,

850., and the relative arrangement of the parts is such that when saidroller or arm engages such cont-act it will press the same toward thecorrespondingcontact 1 3, &c.,and through the medium of the insulation 5will press the last-mentioned contacts into engagement with the contact6. The arm 7 is to stop in connection with a contact of an idleconductor and for this purpose is shown provided with a series of teeth7* and with a broad tooth 7", which are adapted to be engaged by adetent 11, formed on, connected with, or operated by an armature 12,that is shown carried by or part of an arm 12 pivotally supported, as at13, and adapted to be attracted by a magnet 14. The arm 7 is adapted tosweep back and forth across the are described by the contacts abovementioned, (except when stopped by detent 11,) and while these parts areillustrated diagrammatically in Figs. 1, 2, 3, and 4 they are shown morefully in detail in Figs. 5, 6, and 7 in structural form. In thelast-named figures D indicates a suitable frame or box in which theshaft 8 is suitably journaled, and the cont-act 6 is shown carried byposts 6, the

magnet 14 being suitably supported on said box or frame, and the pivot13 is shown supported on uprights 13, the contacts 1 2 3 4 beingsupported on suitable insulation (Z, such as rubber or fiber. The arm 7is to be moved by means of the handle 9 into position to enable it totravel to select the contacts 2 4, &c., and 7 is a stop to limit themovement of said arm by the operator. Said arm is preferably controlledby means of a geartrain E, having a fan c, the spring E of which trainis secured to the shaft 8 and to the frame D in any wellknown manner,whereby as the handle 9 is turned upwardly in the drawings the springwill be wound and will act to depress the arm when said handle isreleased.

The devices described for use at central for selecting idle conductorsare also used at the various stations on a circuit for similarlyselecting the same conductors, but with modifications that will bepointed out hereinafter.

The detent 11 is to'cause arm 7 to come to rest in connection with anidle conductor 2 or 4 and is controlled through the action of magnet 14and its spring 15, the arrangements for which at central A are asfollows: a is a contact adapted to be engaged by arm 7 or' its roller 10and to be thereby pressed into engagement with contact 6. extends aconductor 16, thatleads to a con tact 17, normally engaged by a contact18, controlled by a key 19, (for a purpose hereinafter explained,) whichcontact 18 normally engages a contact 20, connected by a con ductor 21with a battery 22, fromwhich a conductor 23 extends to a contact'24. Thecontact 24 is in engagement with a contact 25 when the detent 11 is inengagement with the broad tooth 7 of arm 7, (which occurs when the arm 7is in its uppermost position ready to descend to select an idleconductor of the party-line.) The contact 24 is controlled by arm 12,operated by armature 12 and having insulation 12 to engage and operatecontact 24. From the contact 25 a conductor 26 leads to magnet 14, andfrom the opposite terminal of said magnet a conductor 27 is electricallyconnected with arm 7. Thus when arm 7 is raised by the operator atcentral to enable it to travel to select an idle conductor-such, forinstance, as 2 in Fig. 1the tooth 7 will act upon detent 11 to move thearmature 12 toward magnet 14 and allow contacts 24 25 to engage. As arm7 now descends it will first engage contact a and move it againstcontact 6, whereupon a circuit for magnet 14 will be established asfollows: From contact Ct through 6 16 17 18 2O 21, battery 22 23 24 2526, magnet 14, conductor 27, and arm 7, back to contact a. Magnet 14will now be energized and will hold detent 11 from engagement with atooth 7 until arm 7 passes into engagement with a contact 2 or 4 of anidle conductor of the party-line, whereupon circuit through magnet 14will be broken, and spring 15 will draw detent 11 into engage- Fromcontact 6 I ment with a tooth 7 of arm 7 to hold said arm in connectionwith such idle conductor, at

the same time moving contact 24 to break the circuit at 24 25. Thus anidle conductor will be selected at central. The relative positions ofthe contacts a 2 4 820., should be such that roller 10 of arm 7 isalways bridged between two of such contacts. Assuming that the pair ofconductors 1 2 in Fig. 1 are idle, the arm 7 will stop in connectionwith them because when the arm passes from contact a the circuit beforedescribed through magnet 14 will be broken and the arm 7 will be stoppedby detent 1.1 in connection with contacts 1 2, arm 7 thereby pressingcontact 1 into engagement with contact 6. As the contact is now brokenat 24 25 the circuit through magnet 14 is open at said points. Thedescribed positions of the parts now enable a subscriber to call centralover the idle conductor so selected. (If arm 7 should have passed over acontact belonging to a conductor that was in use in any station, circuitwould have been kept up through magnet 14 to prevent the arm fromstopping upon said contact, so as to enable the arm to pass on to aconductor not in use, as will be explained hereinafter.)

To permit a subscriber to call central, devices are located at eachstation on the partyline to select the same conductor that the arm 7 atcentral has selected. These devices are substantially the same as thedevices used at central and comprise the arm 7, having teeth 7 and 7 androller 10, armature 12, pivotally carried at 13, arm 12, insulation 12",and magnet 14. In each station also contacts 1", 2", 3 and 4",insulation 5, and a contact 6 are arranged similarly to contacts 1, 2,3, 4, insulation 5, and contact 6 at central, and the contacts l 2, 3and 4 are connected with the conductors 1, 2, 3, and 4, respectively, asby spur wires or conductors 1, 2, 3, and 4. The circuit for magnet 14,however, is somewhat changed from that at central. In this case aconductor 27 leads from arm 7 to contact 24 and a conductor 26 leadsfrom contact 25 to magnet l4,contacts 24 25 being adapted to make andbreak circuit by the action of armature 12, arm 12, and insulation 12.From magnet 14 a conductor 28 leads to ground 29 at the correspondingstation, although conductors 28 could lead to'a return-wire common tothe stations on a party-line. The receivers 30 at the stations B B B 0 C&c., when not in use preferably hang upon hooks 81 in wellknown manner,and the hooks 31 each have or control an arm 32, that is adapted toengage and lift the corresponding arm 7, so as to hold it above or outof engagement with the corresponding contacts 1 2",&c. as shown in Fig.2, and at station 0 in Fig. The arrangement is such that when receiver30 is lifted from its book 31 the arm 32 will descend, thus releasingarm 7 to allow the latter also to descend. It will be understood thatwhen arm 7 is raised by arm 32 tooth 7 will engage detent 11 and holdarmature 12 away from magnet 14,whereupon contact 24 will engage contactas in Fig. 2, and these are the normal positions of the parts. Thepurpose of arm 7 in a station is to select and make connection with thesame party-line conductor that is selected at central,whereb v a callmay be sent to central and telephonic communication established oversuch conductor. For this purpose a battery-circuit is to be establishedfor magnet l4,which I have shown arranged as follows: Passing now to thecentral office A, it will be seen that a conductor 33 leads to anindicating instrument 34 of any suitable kind. The instrument I haveshown is an annunciator having a drop 34. The drop 34 is shown providedwith a finger or projection 34 and adapted to be actuated by key 19 or aprojection or finger 19, connected therewith, to restore said drop toits normal position when key 19 is operated. From the instrument 34 aconductor leads to a contact 36, adapted to be engaged by contact 24when detent 11 is holding arm 7 in connection with an idle party-lineconductor, con-- tact 24 being connected by conductor 23 with battery22. Battery 22 is also connected by a conductor 22 with ground 22,although it could be connected with the common returnwire beforementioned. Now assume that arm 7 at central has selected an idleconductor, as 2, and is held by detent 11 in connection therewith, as atcentral in Fig. 1, and that a subscriber on a party-line at a station,as B, desires to call central. His (the subscribers) instruments mustselect the same conductor that was selected at central, as 2. Thesubscriber now lifts his receiver 30 from hook 31, whereupon arm 32descends and al lows the corresponding arm7 to travel,it beingremembered that tooth 7 by acting on detent llwhen arm 7 was in theupper or normal position allowed contacts 24 25 to engage. Arm 7 nowmakes electrical connection with contact 2 of conductor 2, (likewisepushing contact 1 into engagement with contact 6,) as in Fig. 2,whereupon a circuit will be established between magnet 14 of theoperating-station and the indicating instrument 34 at central asfollows: from ground 29 through 28, magnet 1426, contacts 25, 24, (whichare stillin engagement, asin Fig. 2,) and 27 to arm 7, thence through 2and 2 to conductor 2, (all at 13,) thence along conductor 2 to 2 atcentral and through 27 and 33 to instrument 34, thence through 35, 36,24, 23, battery 22, and 22 to ground 22. Current now flows from battery22 and causes instrument 34 to operate to indicate a call at central andalso energizes magnet 14 at the calling-station B, whereupon armature 12at B is attracted and causes detent 11 to engage a tooth 7 of arm 7,thus arresting said arm in connection with contact 2". Thus it will beseen that by simply raising the receiver 30 from its hook a subscriberis enabled to select a conductor of a party-line that has beenpreviously selected at central and to produce a call atcentral. Thecircuit in a station for the telephone isas follows: From contact 6 aconductor 16 leads to one terminal of receiver 30, and from the otherterminal thereof a conductor 30 leads to a contact 36, that is adaptedto be engaged by contact 24, and this engagement occurs when armature 12is attracted by magnet 14 to cause arm 7to select a conductor of theparty-line. The normal positions of the parts will be seen in Fig. 2.

It will now be shown how telephonic communication can be establishedbetween central and a station, and by preference aclosed metalliccircuit is established for the telephones over the pair of selectedconductors. 37 is a telephone-receiver at central A, from one terminalof which extends a conductor 38, that leads to a contact 39, adapted tobe brought into electrical circuit with contact 40 by a contact 41,carried by key or switch 19 and insulated therefrom. From contact 40 aconductor 42 leads to conductor 33. From the other terminal of receiver37 a conductor 43 leads to a contact 44, normally disengaged from butadapted to engage a contact 45, that is connected by a conductor 46 withconductor 16. Contact 44 is normally held out of engagement with contact45 through the medium of key 19, insulation 44 being shown carried by19. Circuit through the receiver is normally broken at 39, 40, 41, andat 44, 45. The subscriber having called central, as before explained,the operator presses key 19, whereupon a closed metallic circuit throughthe telephones at central and at the calling-station B will beestablished as follows: from arm 7 at central through 27, 33, 42,40, 41,39, 38, receiver 37, 43, 44, 45, (which now engage,) 46, 16, 6, and 1,(which is held in engagement with 6 by arm 7,) to conduc-.

tor 1, thence along conductor 1 to the calling-station B through 1 and 1to 6, (1 and 6 being held in engagement by arm 7 at 13,) thence to 16,receiver 30, 30, 36, and 24, (which are now in engagement,) 27, arm 7,contact 2", and 2 to conductor 2, thence along 2 from B to 2 at centraland to arm 7 again. The calling subscriber then tells central whatsubscriber he wishes and central calls such subscriber, as will beexplained hereinafter. If the called subscriber, as C, is on the sameparty-line as the calling subscriber he merely removes his receiver 30from its hook, whereupon the arm 7 in his station will select and makeelectrical connection with the same party-line conductor with which thecallingstation is already connected. This selection of said conductoroccurs because the arm 7 at central still remains in connection withsaid conductor, and the magnet 14 at the called station will beenergized in the same manner as that described with reference to stationBthat is to say, the circuit will be from ground 29 at C through 28, 14,26, 25, 24, 27, 7, 2", and 2, to 2 at C, thence over conductor 2 tocontact 2 at central, thence through 7, 27, 33, 34, 35, 36, 24, 23,battery 22 IIO and 22 to ground 22*. Armature 12 at C will reaches thecontact 4 of idle conductor 4 and now be operated to cause arm 7 to cometo rest in connection with contact 2", and contacts 24 36 will bebrought together. The telephones in the calling and the called stationsBO will now be in a closed metallic circuit, (shown in Fig. 1,) which isas follows: from arm 7 in station B, through 27, 24", 36, 30 receiver30, 16, 6, 1 1 to conductor 1, thence over said conductor to station 0,through 1, 1 6, 16 30, 30, 36, 24, 27*, arm 7, 2", and 2, to conductor2, thence to station B, through 2 and 2 back to arm '7.

If the subscriber to be called had been located on a party-linedifferent from that on which the calling subscriber was located, theoperator at central would call such subscriber, as hereinafterexplained, who would remove his receiver from its hook 31, and the arm 7at the called station would then select the conductor of its party-linethat had previously been selected by the corresponding arm 7 at central.The operator at central would then connect the selected conductors ofthe two party-lines by suitable devices at central, as will be explainedhereinafter.

Now that I have explained how the arm 7 at central selects and remainsin connection with an idle party-line conductor, how the arm 7 at astation selects the same idle conductor, and how these conductors areconnected together through the telephone at said station it will beconvenient to explain how the arms 7 disregard conductors that are inuse and only select a conductor that is idle. It is the purpose toalways have arm 7 at central inconnection with anidle conductor wheneverthere is one such on a party-line. Assuming that conductors 1 2 are inuse by a subscriber or subscribers on .a party-line, as beforedescribed, as in Fig. 1, the operator at central next turns handle 9,and thereby arm 7, to the starting-point and then releases the same. Arm7 immediately descends, and when it (or its roller 10) engages contact0t the local circuit for magnet 14 at central will be closed, as beforedescribed, to hold detent 11 from teeth 7 Arm 7 next passes to contact2, and when it leaves contact a a new circuit for magnet 14 will beestablished as follows: from arm 7 through 27, 14, 26, 25, 24, (whichare still in engagement,) 23, battery 22, 21, 20, 18, l7, l6, 6, and 1to conductor 1, thence to the station using the line B and through 1 to1 6, 16, receiver 30, 30, 36*, 24 27, arm 7, contact 2 and 2 toconductor 2, thence back to central at 2 and to arm 7 again. Magnet 14will thus still be energized to keep detent 11 from stopping arm 7. Arm7 therefore continues to travel, seeking an idle conductor. If the nextconductors reached by leaves contact 2 the circuit through magnet 14will be broken, because the conductors 3 and 4 will be open'beyond thecentral office. Spring 15 will now draw detent 11 into engagement with atooth 7 of arm 7, thus arresting arm 7 in connection with conductors 34, as shown in Figs. 2 and 3. Thus notwithstanding that conductors 1 and2 are in use a line is established to central for any other subscriberson the same party-line. The arm,7 at central is shown in Fig. 2 on thesecond pair of conductors 3 4, the first pair of conductors beingsupposedly busy.

Now suppose a subscriber on the partyline, say at station E in Fig. 2,desires to call central. He first removes his receiver 30 from its hook,whereupon his arm 7 travels. Arm 7 (at B Fig. 3) first reaches contact2"; but as arm 7 at central is not in engagement with contact 2 therewill be no circuit through conductor 2 to battery 22, so said armtravels on past contact 2 ;but "when it reaches contact 4 a circuit willbe established from ground 29 at B through magnet 14 thereat to ground22" at central, through instrument 34 and battery 22, thus producing acall at central, as before explained, and holding arm 7 in station B incontact with 3*. The position of the parts will be seen in Fig. 3-thatis to say, the arms 7 at central and at station 13 are in connectionwiLh conductors 3 4; but the arm at station C is in its normal.condition. It the subscriber at station 0 should he wanted, his arm 7after he removes his receiver 30 from hook 31 will travel past thecontacts of conductors 1 2 and will be stopped in connection with thecontacts of conductors 3 4, as explained with relation to station B Itwill be understood that after the operator at central ascertains thattwo subscribers are in telephonic communication he will return his arm 7to the starting-point and release it, whereupon it will descend to seekany idle conductor, the object being to always have an arm at central inconnection with an idle conductor of the party-line, provided there issuch idle conductor.

While I have shown a localcircuit at the central office for magnet 14established through contacts a and 6, Fig. 1, by the action of arm 7, asbefore described, it will be understood that this local circuit can bedispensed with, in which case magnet 14 will only be energized to holddetent 11 from teeth 7 when arm 7 engages a contact of a conductor thatis in use by an outlying station over the circuit previously describedthrough said station; but the purpose of this local circuit is to causemagnet 14 to be first energized on a short circuit, so as not to requireit to attract armature 12 by current on a long circuit, and thus whenthis local circuit is used the passage of arm 7 from contact Ct tocontact 2 merely requires the current on the circuit through magnet 14between the central office and an outlying station to besuiticieutly ITOthe devices at a station also select the same selected line and producea call at central, how the devices at central and at a station areadapted to establish a closed metallic circuit through their telephones,and how a closed metallic circuit is established through the telephonesat two stations on one party- 'line, I-will now explain how the operatorat the central office connects together the selected conductors of twoparty-lines and establishes telephonic communication between twostations on such party-lines and also communication between central andsaid subscribers. The arrangement for this purpose is illustrated inFig. 4. The respective pairs of conductors l 2 and'3 4 are provided withjacks 48 or other suitable devices for connecting such conductorselectrically. These jacks are shown composed of contacts 48 48 48 48,con nected, respectively, to condu ctors 1 2 3.4 and arranged in pairs48 48 and 48 48 49 indicates plugs for connection with such jacks andshown connected by wires 50 51 in well-known manner. The plugs 49 areshown having a contact 49 connected with wire 50, and a contact 49",connected with in Fig. 4.

wire 51, which contacts are insulated from each other. By insertingplugs 49 in the jacks 48 of two party-lines the pairs of conductors ofsuch party-lines can be connected, as shown While I have heretoforedescribed an independent circuit for the receiver 37at central for eachparty-line, I have shown in Fig. 4 an arrangement whereby one receiver37 will suffice for a number of party-lines. In this case the parts 16,17, 18, 19, 20, 21, 33, 34, 38, 39, 40, 41, 42, 43, 44, 44, 45, and 46are the same for each party-line, as before de scribed; but theconductors 21 for each partyline are shown connected together at 21 andthe conductors 23 are connected together at 23 The conductors 38 of eachparty-line are shown connected together at 38, one of which leads to oneterminal of receiver 37, and the conductors 43 of each party-line areshown connected together at 43, one of which leads to the other terminalof receiver 37. The conductors 43, however, are connected with a contact52, adapted to be electrically connected with a contact 53 by a contact54, carried by a key or switch 55, but insulated therefrom, preferablyhaving a spring 56 to normally hold contact 54 out of engagement withcontacts 52 53. The contact 53 is connected by a conductor 57 with wire50. The

conductors 38 are connected by a conductor 58 with a contact 59, adaptedto be electrically connected with a contact by a contact 61, carried byswitch or key 55, and the contact 60 is connected by a conductor 62 withwire 51.

When the operator at central desires to communicate telephonicallywith asubscriber on a party-line who has called central, as B, said operatordepresses key 18 at the right in Fig. 4, connected with said party-line,which breaks the circuit of conductor 16 to ground 22 at 17 18 20 andcloses the circuit forthe telephone at 39 4041 and at 44 45,whereuponthe circuit will be from 16, through 46,

45, 4,4, 43, 37, 3s, 39, 41, 40, 42, 33, and 27, to

arm 7, &c. Likewise if a subscriber on another party-line, as B, hadcalled central the operator thereat would operate key 19 at the left inFig. 4, establishing the same character of circuit for receiver 37.After the operator at central has connected two party-lines together bythe jacks 48, plugs 49, and wires 50 51- and he desires to ascertain ifthe subscribers are in communication he operates key 55, keys 19 beingin their normal positions to break circuit at 39 4O 41. Circuit throughreceiver 37 will now be established simultaneously to both party-linesas follows: from the jacks and conductor 50, through 57, 53, 54, 52, 43,37, 38, 58, 59, 61, 60, 62, and 51, back to the jacks. After theoperator at central ascertains that the subscribers are in communicationhe releases key 55,whereup.on the circuit is broken at 52 53 54 and at59 60 61. It will be seen that as contacts 44 45 are at this time out ofengagement the circuit just described is made possible,notwithstand--ing that the conductors 38 of two or more party-lines'and the conductors43 of the same party-lines are respectively joined together at 38 43*.

It will be seen in Fig. 4 that conductors 1 2 of the party-line on theright and conductors 3 4 of the party-line on the left are joinedtogether through the plugs fand jacks while the arm 7 at central at theright is in connection with conductors 3 4 and that the arm 7 at centralat the left is in connection with conductors 1 2 of the otherparty-line. The arrangement shown is for the purpose of illustrating howthe arms 7 at central of the diit'erent party-lines select idle.conductors and disregard conductors that are in use. Therefore assumethat the subscriber at station E called central while the correspondingarm 7at central was in connection with contacts 1 2, for which reasonarm 7 at station E was arrested in connection with conductors 1 2.Assume also that thereafter the operator at central restored arm 7 ofthat party-line to its starting-point and that in its next travel itdisregarded conductors 1 2 and selected the next pair of idleconductors, such as 3 4, whereupon it came to rest to enable anothersubscriber on said party-line to make connection with said conductors.Also assume that when central next called the subscriber at station Bthe conductors 1 2 of the corresponding partyline were in use by someother station and that arm 7 at theleft at central was at rest inconnection with conductors 3 4, so that when the subscriber at station Bremoved his receiver from its hook the arm 7 thereat disregarded theconductors l 2 and made connection with the conductors 3 4. Suppose alsothat after such connection was made the subscriber using conductors 1 2at the left in Fig. 4 had finished and hung his receiver upon its hook,so that when the corresponding arm 7 at central again sought to selectidle conductors it stopped in connection with conductors 1 2, as at theleft in Fig. 4. The foregoing explanation shows how the arms 7 in Fig.4: are enabled to assume the positions shown. The position of the arms 7at central indicate to the operator thereat which conductors of theparty-line are to be connected through their jacks and plugs. Thus theoperator at central is readily enabled to connect the selectedconductors of the calling subscribers partyline with the selectedconductors of a calledsubscribersline. When the subscribers havefinished talking and they hang their re ceivers upon their respectivehooks 31, the corresponding arms 7 at such stations return to theirnormal positions and break connection with the conductors that have beenin use, leaving such conductors in an idle condition ready to be againselected by the arms 7 at central;-

The arrangement I have shown for enabling the operator at central toselect and call the station desired on any party-line without producinga call in any other station, is as follows: Each party-line has aplurality of conductors 66 67, leading through the stations B B C B 0&c., and in each station are located signaling instruments and devicesadapted to select the signalinginstrument of the station desired toestablish a circuit for the same from central and to restore thesedevices and circuits to their normal conditions all by current sent bythe operator at central. The line 65 I term an operatingline, because itis over this line that the selection of the desired signaling instrumentis effected. This line is not a through-1ine from central to eachstation, butis divided in each station or made in sections, the firstsection leading from central to ground at the first station on a circuitand the other sections leading from an open point in one station toground in the next succeeding station, and so on for all the stations ona partyline. The section of line 65 that extends into a station isconnected with a contact 68 and also with a contact 69, as by aconductor 70. The contact 69 in each station is normally in engagementwith a contact 71, that is con nected by a conductor 72 with a magnet73, and the opposite terminal of said magnet leads to ground, beingshown connected by a conductor 74: with the conductor 28, leading toground 29. Thus the section of the partyline that leads from central isnormally grounded in the first station 13 on the partyline and is brokenfrom the section of the line that leads from station E to the nextstation, as C; but these grounds are adapted to be broken and theseveral sections of the line connected together in the stations to forma through-line from central to the station desired. For this purpose ineach station the section of line 65 leading from the station isconnected with a contact 75, that is normally outof engagement withcontact 68, but adapted to be engaged thereby, and the arrangement issuch that when circuit through contacts 6.9 71 is broken circuit throughcontacts 68 and 75 will be established, thus joining two sections of theline together.

The calling-conductor 66 extends unbroken through all the stations on aparty-line; but in each station it is connected with a contact 76, as bya spur-wire 77, and the contact 76 is normally out of engagement with acontact 78, which is connected by a conductor 79 with a signalinginstrument 80, from which a conductor 81 leads to ground, being shownconnected with conductor 28, and thus leading to ground at 29. Thearrangement is such that when contacts 76 78 in any station are broughtinto circuit the signaling instrument in that station can be operated bycurrent thrown on the line 66 from central, as through 66, 77, 76, 78,79, 80, and 81 to ground; but this will not be done until the stationdesired is selected over the operating-line 65.

Any suitable devices may be provided for making and breaking circuitthrough the contacts above mentioned. The arrangement I have shown forthe purpose is as follows: 82 is a cylinder or roller pivotallysupported in a suitable frame 83, Figs. 8 and 9, being shown providedwith a shaft 82, journaled on pivots 84:, carried by said frame. inderis provided with a plurality of projections arranged in series aroundthe periphery thereof, each series being adapted to'con trol a pair ofcontacts. 85 indicates projections for contacts 76 78. 86 indicatesprojections for contacts 68 75. 87 indicates projections for contacts 6971, and 88 89 are projections for other contacts to be described. Bypreference the roller 82 and its projections are made of insulatingmaterial, such as fiber or rubber, so that no circuit will beestablished between the contacts and the roller, although this may beprovided for in any other suitable manner. The relative arrangement ofthese various projections is such as to make and break contact betweenthe corresponding pairs of contacts at the proper times. In thearrangement shown the normal positions of the projections 85 and 86relatively to contacts 76 78 and 68 75, respectively, are such that saidcontacts will be normally disengaged, and the positions of theprojections 87 relatively to the contacts 69 71 are such that saidcontacts will be normally in engagement. The roller 82 is to be rotatedstep by step by means of current sent from central through magnet 73 inconjunction with a spring. For this purpose I have shown a ratchet-wheel90 connected with roller 82, (see Fig. 9,) and 91 is a rod or Saidroller or cylarm carrying pawls or dogs 92 93, adapted to engage andoperate said ratchet-wheel. The rod or arm 91 is shown provided with aforked portion 91, that straddles the shaft 82 and is shown as receivinga bushing or enlargement 94 on said shaft, whereby said rod is guided toreciprocate. The pawls or dogs 92 93 are shown extending in oppositedirections and are so arranged that when rod 91 moves in the directionofthe arrow :1: in Fig. 9 pawl 92 will rotate the ratchet 90 and roller 82the distance of one tooth of the ratchetwheel, thereby moving the pawl93 back over two teeth of the ratchet-wheel, and when rod 91 is moved inthe reverse direction pawl 93 will likewise rot-ate ratchet-wheel 90 androller 82 the distance of one tooth in the same direction, whereupon dog92 will travel over two teeth of the ratchet-wheel. This reciprocationof rod 91 causes roller 82 to be rotated successively in one direction,as shown by the arrow 3 in Fig. 9. The rod 91 is reciprocated throughthe medium of magnet 73 and a spring, for which purpose I have shown thearmature 73 of said magnet as supported by a lever or arm 94, pivoted toframe 83, as at 95, and pivotally connected with rod 91 at 96, and 97 isa spring connected with lever 94 and with frame 83, as by a post 98. Inthe arrangement shown when the magnet 73 attracts armature 73 pawl 92will act to rotate roller 82, and'when spring 97 acts upon lever 94 rod91 will be drawn back and pawl 93 will act to rotate said roller. I haveshown armature 73 as extending parallel to magnet 73, and for thispurpose I have provided polepieces 99, that are connected with the coreof the magnet by screws or the like 100. These screws also supportmagnet 73 in frame 83, and in order to permit adjustment of thepolepieces 99 toward and from the armature 73 I have shown frame 83 asslotted at 101 to receive the screws 100. I have shown the outer ends ofthe pole-pieces 99 as provided with recesses 99 to receive the ends ofthe armature 73 (see Fig. 10,) whereby strong mag netic attraction iseffected. This arrangement of the magnet, pole-pieces, and armatureenables said magnet to lie parallel with the roller 82 in frame 83,while rod 91 can reciprocate at right angles to said roller. In order toprevent the magnet and spring from moving the roller 82 too far at eachstroke of rod 91, so as to assure that the projections carried by saidroller will always come to rest in the exact position requiredrelatively to the contacts to be operated thereby, I provide stopsagainst which the dogs 92 93 can abut. These stops are shown in the formof pins 102 103, carried by arms 104 105, adj ustably connected withframe 83, as by screws 106 107. The stops or pins 102 103 can thus beadjusted so as to cause the dogs 92 93 to come to rest in any desiredposition, and, furthermore, the positions of these stops or pinsrelatively to the dogs is such that when the dogs engage them said dogswill be crowded against the ratchet-wheel 90, whereby the latter will bechecked in its movement and rotation through its momentum will beprevented.

The arrangement for restoring the parts and circuits is as follows: Theline 67, Fig. 1, whichIterm the restoring-line, is normally closedthrough the various stations on a partyline, but is adapted to be brokenin each station and connected with the magnet 73 thereat and thence toground. For these purposes the line 67 is made in normally closedsections between central and the first station and also between theother stations on a line, and each section of line 67 that leads into astation connects with a contact 107, which is normally out of engagementwith a contact 108; but circuit through these contacts can be made andbroken by means of projections 109 on roller 82. The contact 108 isconnected with conductor 72, as by a conductor 110, so that whencontacts 107 108 are in engagement circuit from line 67in a station willbe established from 107 through 108 110 72, magnet 73, 74, and 28 toground 29, whereby said magnet can be energized by current sent fromcentral over the restoring-line. Each section of line 67 that leads intoa station is likewise connected with a contact 111, as by a conductor112, and the contact 111 is normally in engagement with a contact 113,and roller 82 has projections 114, that are adapted to make and breakcircuit through contacts 111 and 113. Each section of the line 67 thatleads from one station to another station is connected with therespective contact 113. In the normal position of the roller 82 theprojections 109 and 114 causecontact to be broken between contacts 107and 108 and to be established between contacts 111 and 113,respectively.

The manner of selecting and operating from central the desired signalinginstrument 80 and of restoring these selecting devices and theircircuits to their normal condition is as follows: If the first stationfrom central on a circuit is desired, as B, the operator at centralsends an impulse over the operating-line 65, which passes from groundand battery at central to contact 69 at the station, thence to contact71, as a projection 87 of roller 82 normally keeps said contacts inengagement,

thence through 72 to magnet 73 and through contacts 76 and 78 to engageto close the calling-circuits, projection 86 moves up toward but doesnot operate contacts 68 75, while projection 87 still keeps contacts 69and 71 in engagement. Projection 109 does not yet cause contacts 107108to be connected, and projection 114 moves on, causing contacts 111 113to disengage. lNhile the parts are in this position current from thegenerator at central is sent over the line 66, which then passes to thestation to be called, B, through 77, 76, 78, 79, 80, and 81 to ground29, thereby pro ducing a call. Both currents are then cut from the linesat central, whereupon spring 97 draws armature 91 back and pawl 93rotates roller 82 forwardly another step, and then projection 85 passesfrom contacts 76 78, thus breaking the calling-circuit in the station.Projection 87 passes from contacts 69 71, thus breaking theoperating-circuit through magnet 73, and at this time a projection 86passes under contacts 68 75, cansing circuit to be closed through them.This action joins two sections of the operating-line together, so thatat this moment there Will be a circuit from central over theoperating-line through the first station to ground 29 at the nextstation. The same movement of roller 82 caused a projection 109 to movecontacts 107 108 into engagement, thus establishing a circuit to ground29 for the section of the restoring-line 67, leading from central to theoperating-station through magnet 73, as follows: from 67, through 107,108, 110, 72, magnet 73, 74, and 28 to ground 29. As it was not designedto signal in the next station, the roller 82 must be again rotated torestore the parts and circuits to their normal conditions. This is doneby throwing current upon the restoring-line 67, which finds ground at29, as before stated, whereupon magnet 73 again attracts armature 73,and rod 91 and dog 92 rotate roller 82 another step forward. Thismovement of the roller moves projection 109 away from contacts 107 108,thus breaking this restoringcircuit, whereupon spring 97 draws rod 91back, and dog 93 rotates roller 82 another step, bringing it to itsnormal position, whereupon projection 87 will close the circuit throughcontacts 69 71, and projection 114 will close the circuit throughcontacts 111 113, thus restoring the parts to their normal positions.

Had it been desired to call a station beyond B an impulse would havebeen sent over the operating-line 65, whereupon the roller 82 at B wouldhave been rotated two steps to disconnect two contacts 69 71 andcontacts 76 78 and to join contacts 68 75 and contacts107108fortherestoringlinethrough magnet 73. Another impulse would thenbe thrown on the party-line 65, which would travel through 68 and 75 inthe first station to the section of line leading to the next station andthence at the last-named station through 70, 69, 71, 72, magnet 73, 7 1,and 28 to ground 29, whereupon the roller 82 at the last-named stationwould be moved one step to join contacts 76 78 for the calling-circuitto break the circuit of the operating-line and the circuit through therestoring-line and close a ground-circuit for said restoring-line. Thesignaling instrument of the desired station is thus selected. Currentnow being thrown on the calling-line 66 passes direct through station Eand at station 0 through 77, 76,78, 79, instrument 80, 81, and 28 toground 29, producing a call. Thereupon current will be thrown on therestoring-line, which first operates magnet 73 in station E to restorethe parts there to their normal con.- ditions, completing the line 67through said station at 111 113, whereupon the current flows over line67 to station 0 and through 107,108,110,72,magnet73,74,and 28 toground29. Magnet 73 will operate to likewise re-' store the instruments andcircuits at station 0 to their normal conditions. Thus it will be seenthat station E can be selected and called without signaling in anystation beyond on the same party-line; also, that station C can beselected and called without signaling in any intermediate station, as B,and any station can be called by sending a separate impulse over theparty-line 65 for each station to and including the desired station. Itwill thus be seen that the operating-line 65 is a normally sectional orbroken line adapted to have the sections joined in each station and thatthe restoring-line 67 is a normally through-line adapted to be brokeninto sections as each station is selected and also that as current issent over this restoring-line the same will be again completed as athrough-line and the operating-line 65 will be again broken intosections.

Any suitable means may be provided at central for sending theappropriate impulses over the lines 65 66 67 to select the stationdesired, operate the signaling instrument 80 thereat, and restore theselecting instruments and the circuits to their normal conditions. Thearrangements I have shown for these purposes are first set by theoperator at central and then operated automatically, and these devicesare as follows: Line 65 at central connects with a contact 115, that isadapted to make and break circuit with a contact 116, that is connectedwith a battery, as 22; but this battery is normally out of circuit withthe contact 116. In the devices shown a conductor 117 connects withcontact 116 and is in electrical connection with a contact 118, that isnormally out of engagement with but adapted to be engaged by a pivotedcontact 119, which is carried by but insulated from a rotative support120, being shown mounted upon insulation 121, carried by said support.Said support is shown in the form of a wheel secured upon a shaft 122,suitablyjournaled, and 123 is a handle connected with said shaft forrotating it. 124 and 125 are steps or pins (shown carried by insulation121; see Fig. 11) forlimiting the oscillation of contact 119. 126 is apin or stop adapted to be engaged by insulation 119, carried by 119,(see Fig. 11,) s0

too

that when the support or wheel is in the home position contact 119 bymaking engagement with said stop or pin will move arm 119 out ofconnection with contact 118. 127

is a plug adapted to be placed in the path of contact 119, so that whenthe latter is moved from the home point and reaches the plug 127 saidcontact will be moved into engagement with contact 118. Thus by means ofthe stop 126 and plug 127 the contact 119 can make and break circuitwith contact 118. Contact 119 is electrically connected, as by aconductor 128, with a contact 129, shown carried by the insulation 121,the contact 129 being shown in the form of a ring or plate, and 130 is acontact or spring that bears upon the contact 129 at all times. Contact130 is connected by a conductor with battery 22, being shown connectedbya conductor 131 with conductor 23 at central, and thereby through thebattery 22 and 22 with ground 22". From this it will be seen that whencontacts 115 116 and 118 119, respectively, are in engagement circuitwill be established from ground at 22 through 222 battery 22, conductors 23 and 131, contacts 130 and 129, conductor 128, contacts 119118, conductor 117, and contacts 116 115 to the conductor 65. For thepurpose of causing contacts 115 116 to make and break circuit as oftenas required I have shown a rocker-arm 132', adapted to operate contact116 to make and break circuit, and the wheel 120 is provided upon itsperiphery with a series of teeth 120 120 adapted to engage and rock thearm 132 as said wheel rotates. The arrangement is such that whencontacts 118 119 are in engagement and wheel 120 rotates its teeth 120120 will rock the arm 132 to make and break circuit at 115 116 totransmit one impulse over the operating-line for each tooth.

The calling-line 66 at central leads to a contact 133, that is adaptedto make'and break circuit with a contact 134, and 135 is a rockerarmpivotally supported and adapted to 0perate contact 133. The arm 135 isto be rocked by a projection or tooth 136, carried by wheel 120, and therelative positions of tooth 120 and projection 136 are such that whiletooth 120 is in engagement with rockerarm 132 to close the circuit at115 116 of the operating -1ine projection 136 will engage rocker-arm 135to close circuit at 133 134 of the calling-line. Contact 134 isconnected by a conductor 135 with an electric generator 137, preferablya power-generator, the opposite terminal of which is connected toground, being shown connected by conductor 137 with conductor 21, thatleads to ground 22 Thus when contacts 133 134 are in engagement thecircuit will be from 22 through 22, 21, 137*, 137,135,134, and 133 tothe calling-line 66, whereupon current will be thrown on said line tooperate the signaling instrument at a selected station.

The restoring-line 67 at central is connected with a contact 138,adapted to make and break circuit with a contact 139, and the contact139 is connected by a conductor 140 with conductor 117. 141 is arocker-arm pivotally supported and adapted to actuate contact 138 tomake and break circuit with contact 139, and 142 is a projection or thelike carried by the wheel 120 and adapted to engage and rock arm 141.

3 The devices just described for controlling the station selecting andcalling circuit are illustrated in diagram in Figs. 1 and 4 and areomitted from Figs. 2 and 3, and in Figs. 11 and 12 these devices areshown in structural form. In this case the shaft 122 is shown journaledin a suitable frame 143, the contacts 116 133 134 are shown mounted uponinsulation 144, carried by said frame, and the contacts 138 139 areshown mounted upon insulation 145, also carried by said frame. Therocker-arms 132 and 135 are shown journaled upon a projection or stud146, carried by said frame, and the rockerarm 141 is shown carried by aprojection or stud 147, also carried by said frame. The rocker-arm 132in Fig. 12 is shown in line with the teeth of wheel 120,.while the projection 136 is shown carried by said wheel at one side of and at adistance therefrom, so asto be in line with rocker-arm 135, pins 136being shown connecting parts and 136. (See Fig. 12.) The projection 142is also shown carried by wheel 120, as by pins or the like 142 but outof line with the wheel 120 and the projecti0n 136, as shown in Fig. 12.The tooth 120 is much longer than the teeth 120 of wheel 120, and tooth120 and projection 136 are shown located side by side; but said toothextends beyond said projection, so that the rocker-arm 132 will remainin connection with said tooth after,

projection 136 has passed from under rockerarm 135. Rocker-arm 141 andits projection 142 are in such position that the latter will operate theformer after tooth 129' leaves rockerarm 132. Conductor 117 is shownleading to the frame 143, and contact 118 is shown carried by and inelectrical connection with wheel 120, so that the circuit will be from117 through frame 143, shaft 122, wheel 120, and contact 118, part ofthe mechanism thus constituting part of the circuit for the restoringand calling lines. The teeth 120* 120 upon wheel 120 each correspond toa station on a party-line, there being as many such teeth as there arestations. The front plate or dial 148 of the frame 143 is-provided withan annular series of holes 149 149 149 to receive the plug 127, each ofsaid holes corresponding to a station on the circuit, and said holes arein such position that when the plug 127 is placed therein it will comein line with the cont-act1l9 or its insulation 119. By this means when astation is to be selected and called the operator at central places theplug 127 in a hole corresponding to such station and turns handle 123moves toward the home point it will operate the rocker-arms 132, 135,and 141 at the proper times, and when said wheel reaches the homepointthe stop 126 will engage the contact 119 or its insulation 119 andrestore it toits normal position, thus breaking circuit at 118 119 andstopping wheel 120. By preference wheel 120 is moved to the home pointby a geartrain 150, that is provided with a fan 151 to retard themovement of wheel 120. The spring 152 of said gear-train is connectedwith a post 153 of frame 143 and with shaft 122 in wellknown manner, sothat as wheel 120 is moved away from the home point said spring will bewound ready to return the wheel when handle 123 is released.

The manner of selecting and calling a station by means of theabove-described devices is as follows: Assume that the first station ona party-line is to be selected and called, as B. The operator at centralplaces plug 127 in the hole corresponding to said station, as 149, andturns handle 123 in the direction of the arrow Z in Fig. 11, whereupontooth 120 rides under arm 132, thus closing circuitat 115 116.Projection 136 likewise rides under arm 135, thus closing circuit at 133134, and projection 142 rides under and past arm 141; but there will beno current on the restoring or operating lines at this moment. Thecontinued move ment of wheel 120 causes contact 119 or its insulation119 to encounter plug 127, whereupon contact 119 will be moved intoengagement with contact 118, and current will flow along theoperating-circuit to station E as follows: from ground 22 at centralthrough 22, battery 22, 23, 131,130, 129, 128,119, 118,wheel 120, andthrough the mechanism to conductor 117, thence through contacts 116 115to conductor 65, leading to station B, thence at B through 70 69 71 72,magnet 73, 74, and 28 to ground 29,circuit being maintained at 116 115and 133 134. Magnet 73 now attracts armature 73, which moves the roller82 one step to close the circuit of the calling-line at 76 78. Thesignaling instrument 80 at B will now be operated over a circuit asfollows: from ground 22 to 22 21 137, generator 137, 135, 134, and 133to conductor 66, thence to 77 at 13, through 76, 78, 79, 80, and 81 toground 29. Handle 123 having been released and wheel 120 now returningto the home point, these circuits are maintained until projection 1.36passes from rocker-arm 135, which breaks the calling-circuit at 133 134,and thereafter tooth 120 passes from rocker-arm 132, thus breaking theoperating-circuitat 115 116, whereupon spring 97 will cause rod 91 tomove roller 82 another step, thereby breaking the calling-circuit at 7678 and the operatingcircuit at 69 71, also breaking therestoring-circuit at 111 113 and closing the restoringcircuit at 107 108through magnet 73 to ground 29, likewise joining two sections of line'at 68 75. Projection 142 next operates arm 141 to close therestoring-circuit at 1 38 139, whereupon a circuit for magnet 73 will beestablished as follows: from ground 22 at central through 22, battery22,23, 131, 130, 129, 128, 119, 118, wheel 120, and the mechanism toconductor 117, thence through 140, 139, and 138 to conductor 67, thenceto 107 at B, through 108 110 72, magnet 73, 74, and 28 to ground 29.Magnet 73 now attracts armature 73 causing rod 91 to move roller 82another step, thereupon breaking the circuit through magnet 73 at 107108 and breaking circuit of line 65 at 68 75, and spring 97 next causesrod 91 to move roller 82 another step, thereupon restoring the roller 82and the various circuits controlled thereby to their normal conditions.When wheel 120 arrives at the home point, contact 119 will be moved outof engagement with contact 118 by the stop 126, and projection 142 willremain under rocker-arm 141, whereupon the impulse-transmitting devicesand circuits at central will be restored to their normal conditions. Hadit been desired to call a station on a party-line beyond B-say thesecond station Cthe operator at central would have placed the plug 127in the aperture corresponding to the second station,

as 149". He would then turn handle 123, and during the movement of wheel120 tooth 120 would pass under rocker-arm 132, and the first of theseries of teeth 120 would also pass under said rocker-arm and come torest against said arm, thus closing circuit 115 116.

'During this movement projection 13 6 passes under and away fromrocker-arm 135 and projection 142 likewise passes under and away fromrocker-arm 141. While the tooth 120 engages rocker-arm 132 the contact119 encounters plug 127 and is thereupon moved into engagement withcontact 118, thus closing the circuit of the operating-line at 118 119,and thereupon current flows to ground 29 over the operating-line, asbefore described, thus causing the roller 82 to move one step. As tooth120 next passes from rocker-arm 132, the circuit will be broken at 115116 and spring 97 will cause roller 82 to move another step, thereuponjoining two sections of the party-line 65 together in the, first stationon the circuit at 68 75, likewise breaking the through-circuit of therestoringline 67 and establishing a circuit for the first sectionthereof at 107 108 to ground 29. When tooth 120 passes under rocker-arm132, circuit for the operating-line will be again closed at 115 116,whereupon current will flow to ground 29 at station O, (the one to becalled,) passing through contacts 68 75 in the intermediate station, andthence to and through 69 71 72, magnet 73 74, and 28 to ground 29 at C,whereupon roller 82 thereat will move one step and close thecallingcircuit thereat through 76 78, &c., to ground 29. Projection 136will now cause arm 132 to close the calling-circuit at 133 134,whereupon the signaling instrument at station 0 will be operated overthe circuit before explained, the circuit, however, passing directlyalong line 66 past the intermediate station, as contacts 76 78 thereatare out of engagement. Projection 136 and tooth 120 next pass fromrocker arms 135 and 132, breaking the circuits, whereupon spring 97 willcause roller 82 to move another step to establish a circuit to ground 29at C for the second section of the restoringline, and

thereupon projection 142 will cause rockerarm 141 to close circuit at138 139. Roller 82 at B will now be moved to restore the cir cuits totheir normal condition, thus closing circuit over restoring-line 67 at111 113 in B to enable current to flow through magnet 73 to ground 29 atO, whereupon magnet 73 at .0 will cause roller 82 to move one step tobreak the circuit at 107 108 and reestablish circuit at 111 113. Thus itwill be seen that'when current is sentover restoring-line 67 the rollers82 in the stations that have been operated will be returned successivelyto their normal positions.

From the foregoing it will be understood that wheel 120 has a tooth forevery station on acircuit, that tooth 120 corresponds in action to thestation to be called, and that this tooth is preferably longer than theteeth 120 to cause the calling-circuit at the desired station to be heldclosed while current is being transmitted over the calling-circuit. Thusfor every station on a circuit between central and the station to becalled a tooth 120 passes under rocker-arm 132, and thereby as wheel 120returns to the home pointan impulse will be sent over the operating-lineto cause the proper connections to be made in each intermediate stationor stations to establish a through-line out of the sections of theoperating-line to ground at the station desired. Therefore the operatorat central by placing a plug 127 in the aperture corresponding to thestation desired and turning handle 123 until it comes to rest sets thesubscriber selecting and signaling devices in operative condition, andas wheel 120 returns to the home point automatically the desired stationwill be selected and signaled to and the circuits and devices restoredto their normal conditions without signaling in any station between orbeyond central and the station called. These subscriber selecting andsignaling devices have been described with reference to a singleparty-line, and one set of such devices may be used for selecting andsignaling the subscribers on a number of party-lines. The arrangement Ihave shown for enabling the operator at central to switch these devicesinto circuit with any desired partyline of a number of such lines areshown in Fig. 4 and are as follows: The sections of line 65 that leadfrom central on the various party-lines each start from a contact 65,and 65 is a contact adapted to be brought into electrical connectionwith either contact 65 by a contact 65, carried by and insulated from anarm 156. From contact 65 a con ductor 65 extends to contact 115, so thatwhen contact 65 engages contacts 65 and 65 the circuit will be from 117through 116 115, (when they are in engagement,) 65, 65, 65, and 65 tothe corresponding section of line 65. The calling-line 66 for eachparty-line connects at central with a contact 66, that is adapted to beengaged by a contact 66, carried by and in electrical engagement witharm 156, and from arm 156 a conductor 66 leads to contact 133, so thatwhen contact 66 is in engagement with a contact 66 and contacts 133 134are also in engagement the circuit will be from ground 22 through137,generator 137, 135, 134, 133, 66, 156, 66", and 66 to the conductor66 of the party-line of the station to be called. At central the sectionot'each restorlug-line 67 leadstoacontact67,thatis adapted to be engagedby a contact 67 carried by and insulated from arm 156, and contact 67 isadapted to engage a contact 67, that is connected by a conductor 67 withcontact 138, so that when contacts 67, 67, and 67 and contacts138 and139 are in connection the restoring-circuit will be from 117, through140, 139, 138, 67, 67, 67, and 67, to the corresponding section of therestoring-line 67. Now if a subscriber is to be called on the party-linehaving stations B and O the operator at central turns arm 156 to bringcontacts 65 65 65 and 66 66 and contacts 67, 67 and 67, respectively,that belong to that party-line, into electrical engagement. Likewise ifa subscriber on a different party-line is to be called the operator atcentral will move the arm 156 to bring the corresponding sets ofcontacts into-electrical engagement for that party-line. By this meansthe devices at central for selecting and signaling to a subscriberarethrown into circuit with the corresponding conductors of the requiredparty-line. The arm 156 and the corresponding contacts connected withthe party-lines and interposed in Fig. 4 between the transmitting deviceand the lines 65, 66, and 67 are shown in Fig. 1 to enable the operatorat central to switch the transmitting device onto any desiredparty-line.

The complete operation of a central-office party-line system installedin accordance with my invention may be summarized as follows, and I willdescribe the same more particularly in connection with Fig. 4:First,.suppose that the subscriber at B on one partyline desires to callthe subscriber at B on another party-line. It will be assumed that thearm 7 at central belonging to the partyline of station B is at rest inconnection with contacts 1 2 of conductors 1 2, as shown in Fig. 1, andthat the arm 7 at central of the party-line of station B is at rest inconnection with contacts 3 4 of conductors 3 4 of- I that party-line, asin Fig. 4, and that the plugs 49 are not yet connecting the said pairsof conductors. The subscriber at station E now removes his receiver 30from its hook 31, whereupon his arm 7 travels, and when it reachescontact 2 circuit will be established to ground 22,through battery 22 atcentral, from ground 29 at B for magnet 14 at B and indicatinginstrument 34 at central. Drop 34 now operates, and magnet 14 at Bcauses detent 11 to stop the arm 7 in connection with contact2".

The operator at central now responds by explained.

pressing key 19, thereupon closing circuit at 39 4O 41, at4445,alsorestoringthe drop 34 and breaking circuit at 17 18 20. The subscribernow tells the operator at central the number of the subscriber hedesires, whereupon the operator at central releases key 19 and swingsarm 156 so as to connect his subscriber selectingand signaling deviceswith the party line of the station desired B. The operator thereuponplaces a plug 127 in the aperture 149, &c., corresponding to the desiredstation and turns handle 123 until it comes to rest, thereupon releasingthe same. Wheel 120 now returns to the home point, thereuponestablishing circuit over the party-line to the desired station,producing a call thereat over line 66 and restoring said circuits andtheir devices to their normal condition over line 67, as beforedescribed. The operator at central may then raise arm 7 of the selectingdevices belonging to the circuit of station E to enable it to select andmake connection with an idle party-line of said circuit, whereupon itwill come to rest in the position shown in Fig. 4 in connection withcontacts 3 4. The subscriber at B hearing the call removes his receiver30 from its hook 31, whereupon his arm 7 will travel down and willdisregard the idle conductors 1 2 ofits circuit and will establishconnection to central over conductor 3, with which the corresponding arm7 at central is now in connection, as before The operator at central byobserving which pair of conductors of the partyline had been selected bythe corresponding arms 7 next connects such conductors by the jacks 48,plugs 49, and wires 50 51, Whereupon conductors 1 2 of the party-line ofstation B and conductors 3 4 of the partyline of station B will bejoined in a closed metallic circuit, as shown in Fig. 4, which circuitmay be described as follows: from arm 7 at station B, through 27, 24,36, 30, receiver 30, 16, 6, 1 1, and conductor 1 to contact 48 of jack48 at the central office, thence by wire 50 to contact 49 of the nextplug 49, thence to contact 48 of the jack 48 of conductors 3 4 of theparty-line of station E, thence through conductor 3 to 3 at B, thencethrough 3", 6, 16, 30, 30, 36, 24, 27, 7, 4 and 4 to conductor 4, thenceto contact 48 of jack 48 and contact 49 of plug 49 at central, throughwire 51 to contact 49 of the plug 49 and contact 48 of jack 48 of theparty-line of station E, thence through conductor 2 of that partyline to2 at B, and through 2 to arm 7again. Closed metallic circuit is thusestablished through the telephones at the calling and the calledstations. The operator at central may determine that said subscribersare in communication by pressing key 55, thereby closing circuit at 5253 54 and at 59 6O 61 through the receiver 37 and wires 50 51, therebyestablishing a circuit for his receiver with the circuit of thesubscribers, and he thereafter releases key 55. then return the arm 7 ofthe party-line of sta- The operator at central may with them, as shownin Fig. 4. When the subscribers have finished talking, they hang theirreceivers 30 upon theirrespectivehooks,whereupon the corresponding arms7 are restored to their normal positions to break the circuit with theconductors that have been in use by them. It will be understood that ifanother subscriber on the same party-line attempted to call central hecould not find a circuit over conductors of the party-lines that wereconnected by the jacks and plugs, as shown in Fig. 4, for the reasonthat when his arm 7 reached the contacts connected with such conductorsit could not find acircuit to ground at central for its magnet 14, and.it would thereby pass onto the first idle conductor in its path. It willbe understood that grou nded circuits may be utilized instead of closedmetallic circuits for the telephones.

While I have described a telephone system having party-lines, it will beunderstood that the party-lines can be connected at central with theordinary telephone-circuits in Wellknown manner.

I do not limit my invention to the precise details of construction shownand described, as they may be varied without departing from the spiritthereof.

A clearing-out signal at central may be provided as follows: Ahigh-retarding target 175 and battery 176 are bridged across theplugcord strands 50 51 by means of conductors 177 178, which are shownconnected to wires 57 and 62, respectively. When a plug is in aline-jack at central and a receiver at a station is in circuit with thecorresponding line, the target is operated to display a signal, and assoon as said receiver is hung upon its hook the target 175 isdeenergized, thereby giving a clearing-out signal. When two subscribersare in communication, as in Fig. 4, the target will show that the lineis in use until both receivers are placed upon their respective hooks.

Having now described my invention, what I claim isi 1. A telephonesystem comprising a central o'ffice, a plurality of conductors leadingtherefrom, a movable arm or contact at central to make connectiontherewith, devices having a magnet to check said arm, a circuit for saidmagnet having contacts that are closed when said arm is at thestarting-point and adapted to be broken to cause the devices to operateto check the arm, an indicating instrument at central, a circuittherefor connected with said arm and adapted to be established over saidconductor when said devices operate to check the arm, whereby saidindicating instrument will be placed in circuit with the conductorselected by said arm.

2. A telephone system comprising a plurality of conductors, a movablearm or contact tomake connection therewith, devices having a magnet tocheck said arm, a circuit for said magnet having contacts that areclosed when said arm is at the starting-point and adapted to be brokenwhen the devices operate to check the arm, an indicating instrument, acircuit therefor connected with said arm adapted to be establishedoversaid conductor when said devices operate to check the arm, anothermovable arm or contact, and electrically-operating devices thereforhaving a magnet, the circuit for said magnet having contacts adapted tobe broken when said arm makes connection with the conductor that hasbeen selected by the first-mentioned arm.

3. A telephone system comprisinga plurality of conductors, a movablecontact or arm to make connection therewith, devices having a magnettocheck said arm, a circuit for said magnet having contacts that areclosed when said arm is at the starting-point and adapted to be brokenwhen the devices operate to check the arm, an indicating instrument, acircuit therefor connected with said arm, normally broken, and adaptedto be closed when said devices operate to check the arm whereby saidindicating instrument will be placed in circuit with the conductorselected by said arm, and other electrically-operating devices adaptedto check said arm and having a magnet, a circuit for said magnet hayingcontacts adapted to be broken when said arm makes connection with theconductor that has been selected by the first-mentioned arm, andtelephone instruments having a normally open circuit provided withcontacts adapted to be closed when the last-mentioned contacts areseparated.

4. A telephone system comprisinga plurality of conductors, contactsconnected therewith, a movable arm to connect with contacts, a magnet, acircuit'for said magnet leading to said arm, a detent to control saidarm and adapted to be operated by said magnet, contacts in said circuitto be controlled by said magnet, and means for establishing circuitthrough certain of said conductors whereby when said arm reaches aconductor that is in use circuit through said magnet will be maintainedand when said arm reaches an idle conductor circuit through the magnetwill be broken and the detent caused to hold said arm in connection withsaid conductor.

5. In a telephone system the combination of aplurality of conductors,contacts connected with said conductors, an arm adapted to engage saidcontacts, a magnet, a circuit connecting said magnet with said arm,contacts in said circuit, a detent, an armature for said magnet adaptedto operate said detent, an arm to be operated by said armature to makeand break said contacts, and a spring to coact with said arm, wherebywhen the first-mentioned arm reaches a contact of an idleconductor-circuit through said magnet will be broken and the arm will bestopped in connection with said conductor.

6. In a telephone system the combination of a plurality of conductors,contacts connected with said conductors, an arm adapted to engage saidcontacts, a magnet, a circuit connecting said magnet with said arm,contacts in said circuit, a detent, an armature for said magnet adaptedto operate said detent, an 'arm to be operated by said armature to makeand break said contacts, a spring to coact with said arm, and means forestablishing a circuit through certain of said conductors, whereby whensaid circuit is so established and the arm reaches a conductor that isin use said magnet will be energized to permit said arm to find aconductor that is idle, and whereby when said arm finds such idleconductor circuit will be broken through said magnet to cause the detentto stop the arm in connection with such conductor.

7. In a telephone system the combination of a plurality of conductors, acontact for each conductor, an arm adapted to connect with the contacts,a magnet, a circuit connecting said arm with said magnet and havingcontacts, devices to be operated by said magnet adapted to check saidarm and break the circuit through the magnet, an indicating instrument,a circuit for the same leading to said arm and having contacts adaptedto be operated by the devices that check vthe arm, means for causing thecircuit through .the magnet to be established when the arm reaches aconductor that is in use, and means for selecting the conductor that isconnected with said arm.

8. In a telephone system a plurality of condoctors and means forselecting and maintaining connection with an idle conductor, incombination with an arm at a subscribers station, a magnet, a circuitfor the magnet leading to said arm, and devices adapted to be operatedby said magnet to break its circuit and check said arm in connectionwith a selected conductor.

9. In a telephone system a plurality of conductors and means forselecting and maintaining connection with an idle conductor, incombination with an arm at a subscribers station, a magnet, a circuitfor said magnet leading to said arm and having contacts, de-

vices to be operated by said magnet to break the-circuit of said magnetand check said arm in connection with a selected conductor, a telephoneinstrument, and a normally open circuit for said instrument adapted tobe closed through said arm when said devices are operated by saidmagnet.

10. A telephone system comprising a central oflice, a party-line leadingtherefrom having a plurality of conductors, an indicating instrument atcentral, devices at central to select an idle conductor and establish acircuit for the same through the indicating in- IIO

